What does « Sheikh / Old man » mean in the Quran?

She said, "Woe to me! Shall I give birth while I am an old woman and this, my husband, is an old man? Indeed, this is an amazing thing!"

They said, "O 'Azeez, indeed he has a father [who is] an old man, so take one of us in place of him. Indeed, we see you as a doer of good."

And when he came to the well of Madyan, he found there a crowd of people watering [their flocks], and he found aside from them two women driving back [their flocks]. He said, "What is your circumstance?" They said, "We do not water until the shepherds dispatch [their flocks]; and our father is an old man."

It is He who created you from dust, then from a sperm-drop, then from a clinging clot; then He brings you out as a child; then [He develops you] that you reach your [time of] maturity, then [further] that you become elders. And among you is he who is taken in death before [that], so that you reach a specified term; and perhaps you will use reason.